Collins completes F-35 EPACS altitude testing

Altitude testing has validated performance of the Enhanced Power and Cooling System, adding thermal margin to support future F-35 technology upgrades.

Collins Aerospace, an RTX business, has completed altitude testing of its next-generation Power and Thermal Management System (PTMS), the Enhanced Power and Cooling System (EPACS), for the F-35.

EPACS delivers increased cooling capacity for the aircraft, providing the thermal margin needed to support planned technology upgrades throughout its service life. The system was run for several days at power levels replicating mission requirements, then pushed to operational limits across a range of altitudes to collect performance data.

Ira Grimmett, vice president, Environmental & Airframe Control Systems for Power & Controls at Collins Aerospace, says: “Successful altitude testing validates system performance in real‑world flight conditions. Completing this phase of testing advances EPACS maturity and reinforces confidence in the system’s capability and performance.”

The trials also confirmed that EPACS can deliver the emergency power required during operation, validating the system’s performance models. The work follows a 2025 confirmation that EPACS met requirements for aircraft integration, with altitude testing forming a further stage in reducing development risk ahead of wider fielding on the F-35.